US2007168A - Process and product relating to halohydrins - Google Patents

Description

July 9, 1935. c. T. KAUTTER- PROCESS AND PRODUCT RELATING TO HALOHYDRINS Filed Feb. 27, 1935 Sample Dmw off.

/ Pressure Gouqe Buffer Tonk 7 lnvznfor: Curl T UNITED STATES PROCESS AND PATENT joFFlcE..

PRODUCT RELATING TO HALOHYDRINS Carl T. Kautter, Berkeley, Calif., assigner to Shell Development Company, San Francisco,

Calif., a corporation oi' Application February 27,-

Delaware `1933, serial No. 658,757

21 l(Cl. 260-157) This invention relates to the manufacture of halohydrins and to certain of the products 'obtained thereby and more particularly is concerned with the preparation of chlorohydrins from hypochlorous acid or its components chlorine and f tine, pentine, dlolenes as allene, butadiene, isoprene, alcohols as cinnamyl alcohol, aldehydes and ketones as acrolein, coumarin and ketenes, halides as vinyl chloride, allyl chloride,.isobu tenyl chloride, acetylene dichloride, amines as allyl amine and the like. The main purpose is P to utilize an unsaturated organic compound which can be maintained in a vaporous state at a temperature and pressure at, which the generated or free hypohalogenous acid does not decompose.

Instead of employing the pure compounds severally or in combination, one may resort to mixtures thereof with relatively unreactive substances. For example, mixtures of olenes and I paraflnes may be resorted to. These may be obtained by the pyrogenesis or cracking of mineral oils such as petroleum oil, shale,v oil, by the destructive distillation of various kinds of brown coal, by the cracking of natural carbonaceous material as petroleumproducts, tars, pitches, asphalts and the like.

In utilizing cracked petroleum products, I find it desirableA to fractionate the same into fractions predominantly containing hydrocarbons containing the same number of carbon atoms to the molecule such as a propane-propylene cut, a butane-butene cut (which contains isobutane, normal butane, butene-l, butene-2, isobutylene and possibly some diisobutylene, a rpentaneamylene cut similar to the butane-butene fraction and the like. By this means one is able to obtain relativelypur products from hydrocarbon mixtures obtained from petroleum products'. If desired, one can rst remove iso-olenes (tertiary) 'from such fractions or original mixtures and treat them independently. Separation may be effected by fractionation and/or condensa'- tion, selective extraction or the like. This permits the recovery of substantially pure halohydrins and permits greater ease of control of the reaction. Very steady running conditions can be established; in circulating systems, the temperl0 ature of the circulating solution can easily be kept within the desired limits.

Where relatively unreactive materials, such as the paran-lne hydrocarbons, accompany the unsaturated organic compound or compounds to be l5 treated, the inert material, upon liquefaction or condensation, may serve as suitable extractant for the halohydrins since the former are substan-` tially immiscible with water and generally miscible with the halohydrins. The oily solution of halohydrin which results can then be easily separated from the aqueous phase and the former subjected to distillation at a temperature and pressure at which the solvent and solute are practically completelyseparated. In the case of ymixtures of olenes and paraines, including suitable fractions such as a butane-butene cut and the like, undergoing treatment, the parafne hydrocarbons will be distilled prior to the vaporization of the halohydrin content. On removal of the parafiin hydrocarbon from its solution with chlorhydrin and water by distillation, thev chlorhydrin may be left in a substantially anhydrous condition. The water present in the solution will be distilled therefrom with the parailln hydrocarbon, since the additive vapor pressures of the hydrocarbon and Water will be greater than atmospheric pressure at temperatures below the atmospheric boiling temperature of water. Mixtures whose parafne content distill off below 100 C. are eminently satisfactory.

Where normally gaseous mixtures are employed under conditions whereat the inert material is not liquefied, it forms part of the atmosphere of the zone of reaction and from time to time is vented, otherwise the reaction zone would finally have an atmosphere composed of an inert gas or gases. Y

Where water, chlorine and oleflne are employed to form `chlorohydrin, the relationship between 50 (l) Giri-H10 The reactions describe a case of mobile equilibrium wherein reaction (2) occurs with greater velocity than reaction (3) or any of the others provided certain conditions are observed which will be described hereinafter.

When the concentration of chlorhydrin in water has reached about 1N., the absorption of oleflne and chlorine in the aqueous solution of hypochlorous acid becomes markedly slower. Higher concentrations are reached only at the expense of a good deal of oleflne, since with the increase of concentration in chlorhydrin proportionately more and more of the products of reactions (3). (4), (5) and (6), especially of (3), are produced.

Prior investigators operated under the theory that it was necessary to depres the influence of hydrochloric acid which is formed in an equivalent amount with hypochlorous acid in order to avoid side reactions and principally. the formation of dichlorides. To attain this end, various salts were added to the reactants which not only did not effect their purpose but, by their presence, enhanced the yield of by-products and especially that of dichlorides. For example, alkalineearth metal chlorides in 2N. concentrations are about twice as effective as 2N.HC1 in inducing the formation of dichlorides and alkali-metal chlorides are even relatively worse.

Neutralization of the hydrochloric acid is not necessary unless it be desirable to avoid the corrosive action of the acid upon the distillation vessel. 'Ihe neutralization of hydrochloric acid is of little effect as regards the concentration of chlorhydrin attainable. Further, it seems as if the rate of combination of unsaturated body and HOCl is somewhat slower than when the hydrochloric acid is left unneutralized.

If, therefore, free hydrochloric acid is permitted to remain in the system, a faster rate of chlorhydrin formation is possible. However, due to the deleterious effect of the conjunctive influences of chlorhydrin and hydrochloric acid. it is desirable to maintain a control on their relative concentrations in the aqueous system so as to obviate dichloride formation and other side reactions.

By operating with an aqueous solution wherein the product of the chlorhydrin concentration and that of the hydrochloric acid is not permitted to exceed about 0.7, expressed in terms of N. solutions, I can practically avoid the formation of dichlorides and the like provided no free chlorine is present in the system in the gaseous phase. Since it is desirable to operate a process so as to obtain the highest practical concentration of chlorhydrin in order to keep recovery and concentration costs low, the practical operating max-- imum concentration of chlorohydrin in water in a circulating systeml would be about a 0.85 N. solution of chlorohydrin while that maximum of hydrochloric acid would, under that condition, comprise about a 0.85 N. solution. It can readily be seen wherein this factor could be varied within lower concentrations to obtain good results. Of course, if the concentrations are kept too low and under the maximum value described, recovery costs of chlorohydrin increase. A practical range is one wherein the product of concentrations of chlorohydrin and HCl lies between about 0.4 and about 0.7. Once the predetermined concentration of chlorohydrin in the circulating system is established and maintained, the concentrations of hydrochloric acid and chlorohydrin can be adjusted to suit the conditions by intermittently or continuously withdrawing a portion of the solution containing chlorohydrin and hydrochloric acid from the system and adding water and chlorine to the system in lieu thereof.

For purposes of convenience, I will employ the term oleflne in the specification to exemplify the unsaturated organic compounds which are embraced by my invention. It is to be understood, however, that the compounds mentioned e lier as well as their homologues and analogues a also suitable.

It is essential that contact of olefine with chlorine in the gas phase be avoided as this will lead to immediate dichloride formation. Accordingly, I resort to a solution of chlorine in water whereby a homogeneous liquid phase is present. Whether chlorine, as such, is introduced into a body of water or whether an aqueous solution of hypochlorous acid is produced electrolytically or by metathesis, etc., does not inatter so long as the aqueous solvent containing the `solute is maintained as a single liquid phase. A mobile equilibrium will be established in this phase and is represented by the reaction Consequently, oleflne, which is subsequently introduced therein, can react only with the chlorine in solution and not with gaseous chlorine. As the rate of reactivity of olefine with hypochlorous acid is much greater than that with' olefine and chlorine in solution, substantially only chlorohydrin will be formed.

Now if an excess of olefine is employed, the formation of addition products (dichlorides) and the like is further obviated. However, I have noticed that the chlorohydrin formation proceeds much faster and smoother, without formation of by-products if an absorption surface as finely divided as possible is presented to the olene. Accordingly, I take advantage of the phenomena which influence the rate of chlorhydrin formation by proceeding substantially as follows.

I establish and maintain a body of water which also contains chlorine, hypochlorous acid and hydrochloric acid in equilibrium. To this, I add, batchwise, intermittently or continuously, the unsaturated organic body. The reaction takes place in a reaction unit from which the air has been displaced by an atmosphere of the unsaturated revaction unit for the reagent and the solution. So

long as unattacked unsaturated reagent remains ain the sphere of reaction, the reaction merely goes to'the formation of chlorohydrins, and the unsaturated reagent exercises a protective. action shielding the product fromI further attack.

The absorption efliciency is helped by the presence of a dispersing agent in either or both fluid reactants which decreases surface tension. Suitable agents well-known to the art as wetting-out agents, dispersing agents, protective colloids and the like may be used. As examples, the sulfonic acids, the fatty acids, preferably the higher ones,

Aamino acids, glue, etc. are suitable.

The degree of hydrolysis of chlorin depends'very much on the efliciency with which the formed hypochlorous acid is removed from the solution by the unsaturated organic body. `If the process is being conducted in an intermittent or continuous manner, water is from time to time added to a circulating stream of hypochlorous acid solu'- tion while chlorohydrin, water and hydrochloric Aacid is being removed from time to time to maintain the operating concentration of HOCl and HC1 in the circulating system.

The presence of some chlorohydrin in the solutio'n at the beginning of the operation seems to increase the speed of absorption of the unsaturated reagent. Accordingly, it is desirable to first build up to the proper concentration of HOCl and HC1 before drawing oif chlorohydrin, HC1 and H2O. ,e

In the accompanying illustration I have shown, more or less diagrammatically, a generalized type of apparatus which may be used in many of the reactions described herein. In this showing Reference character I indicates a spray chamber of a suitable capacity which may be iitted with one or more atomizers for the aqueous solution of hypochlorous acid and hydrochloric acid. It may also be provided with one or more means of introducingthe oleine or unsaturated organic body. The unsaturated fluid body may be directly contacted with the sprayed aqueous solution and/or,

if in the gaseous state, bubbled through a body of aqueous solution contained in the spray chamber. The pressure in the chamber may be atmospheric, superatmosphericor one below atmospheric depending on specific operating conditions and the economies of the procedure adopted.

The chamber I is in communication with a suitable scrubbing tower 2 of any conventional type which may contain packing, perforated plates, and the like and which is provided with means 3 ofintroducing halogen such as chlorine into the column. The communicating conduit 4 between chamber I and tower 2 is so constructed as to permit steady flow of the circulating stream from the chamber to the tower and is equipped with draw-olf means 5 and S. Draw-off means 5 is adapted for the removal of water-insoluble products, such as dichlorides, which may form during the course of the reaction. Draw-off means 6 is effective for draining off halohydrin, hydrochloric acid and water from the system. If a solvent for halohydrin has been employed or a paraiine hydrocarbon utilized in conjunction with an olene, the solvent or parane hydrocarbon agent. The unsaturated reagent (liquid gaseous) is introduced, under pressure, into a will be removed through means 6 if the halohydrin mixture is lighter than water; otherwise al# velocity rates, the halogen is hydrolyzed before entering the spray chamber. Thus, any contact of lgaseous or vaporized unsaturated organic body with gaseous halogen is completely avoided. Lines 8 are equipped with spraying, atomizing or j etting devices 9 so that the resulting acid solution may be introduced'in a nely divided state into the chamber. 'I'he atomizing of the solution in the spray chamber provides such an effectiveness of absorption of the hypohalogcnous acid by the unsaturated organic body that the solution when leaving the chamber is practically -free of halogen.

A filter III may be interposed between vessel 1 and a pump I I for the purpose of removing grit, to prevent injury to the pumping system and clogging of the atomizers. The pump II is preferably provided with a by-pass I2 for controlling the output.

Fresh water may be introduced into the system at I3 although it can easily be seen where it can be introduced in part before the halogen inlet and in part after said inlet or may even be introduced in lines 8 after the pumping mechanism or in the spray chamber itself.

Conventional valve-systems, pressure gages, and draw-off cocks may be installed wherever deemed necessary.

The operating procedure is generally as follows:

The spray chamber I is lled with the gaseous or vaporized unsaturated organic compound with or without attendant inert material so as to exclude all the air. The buffer tank 1 is filled with fresh water and the temperature is maintained at or below C. preferably from about 5 to 20 C. The pump I I is started and adjusted to such output as provides a suitable spray in the atomizing chamber I, the pressure on the nozzles varying from 5-30 lbs. (gage). The water is now circulating from the buffer tank 1, through the lter I0, the pump I I, the spray chamber I, and returning down the scrubbing towerA 2 to the buffer tank 1, in this manner contacting the unsaturated material in the spray chamber.

Halogen is now introduced continuously into the scrubbing column at any convenient point. 'I'he purpose of feeding the halogen into the column is to obtain the full benefit of the scrubbing action ,of the water. However, the exact point of introduction of halogen is not of primary importance as long as it is completely hydrolyzed before entering the spray chamber.

The unsaturated organic compound is now introduced continuously into the spray chamber, at thel ratio of about 1 mol. per one mol. of dissolved halogen.

The following advantages flow from my process. Effective absorption of the unsaturated compound is achieved by bringing the solution containing hypohalogenous acid and hydrochloric acid into an extremely fine'divided form. In this manner, a large excess of gas or vapors of the unsaturated compound or compounds can be maintained in the reaction chamber at all times. This excess is entirely independent of the amount of solution in operation.

Any direct contact of gaseous reagent and halogen which does always occur with stirring equipments and which is undesirable due to the formation of dichlorides is completely avoided.

The hypohalogenous acid is preferably continuously generated outside the reaction charnber. A certain amount of time elapses between the introduction of the halogen and the discharge of the hydrolyzed solution into the reaction zone. This is favorable for a greater degree of hydrolysis in a technical process.

The halogen input, and thereby the capacity of the apparatus, is determined by the absorption eiliciency of the atomizing chamber. This input may be increased to a point where freehalogen just begins to be noticeable in the atomizing chamber.

The following are some of the experiments carried out in a system as described above. 'I'hey are to be regarded as illustrative only.

Example (1) Charge of water in system 6000 cc. Running time 6 hours Chlorine introduced 4.25 mols. Ethylene introduced 4.25 mols. Average temperature of solution Average rate of circulation 1 1 C. 3.0 liters/ minute Average pressure on nozzles 21 lbs. Theoretical ethylene chlorohydrin yield 4.25 mols. Actual yield 3.75 mols.

Example (2). -Butylene Charge of water into system 8300 cc. Running time 7 hours Chlorine introduced 7.4mo1s. -Butylene introduced 7.3 mols. Average temperature of solution 15 C. Average pressure on nozzles 28 lbs. Average rate of circulation 2 liters/min. Theoretical chlorohydrin yield 7.4 mols. Actual yield chlorohydrin 5.8 mols.

This corresponds to a yield of 78.3%-chlorine basis. 79.4%--butylene basis.

The capacity of the apparatus was then:

The final concentration of chlorohydrin in the =0.10 mols./hour per liter solution.

solution was kept at 7.5% 'or 0.69 N. i The con-v centration of HC1 was: 3.0%=0.82 N.

Example (3). Isobutylene Charge of water into system 12000 cc.

Actual yield (chlorohydrin) 7.67 mols.

This corresponds toa yield of 79%-chlorine basis. 77.5%-isobutyiene basis.

The capacity of the apparatus lwas then:

The nal cencentration of chlorohydrin in the solution was kept at 8.5%=0.78 N. The concentration of HC1 was 3.1%=0.85 N.

Example (4). Mixture of isobutylene and n- =0.10 mols. per liter solution per hour.

butane The gas used was of the following composition: Isobutylene 57.8% Total olefines 63.5% n-Butane 36.5% Charge of water into system 5700 cm.3 Running time 5 hours Chlorine introduced 4.1 mols. Gas introduced'. 8.2 mols. Olene content of gas 5.2 mols. Average temperature of solution 18 C. Average pressure on nozzles 28 lbs. Average rate of circulation 2.2 liters/min. Theoretical isobutylene-chlorhydrin-yields 4.1 mols Actual yield (chlorhydrin) 3.16 mols.

This corresponds to -a yield of 77.1%-chlorine basis. 63.2 %-olefine basis.

The capacity of the apparatus was then:

The final concentration of chlorhydrin in the solution was kept at 5.8%:054 normal. The concentration of HC1 was 2.81%=0.77 normal (normality product: 0.415). In this case (olefine impure with 36.5% inert material) a second spray chamber will increase the yield (oleiine basis).

While I have in the foregoing described in some detail the preferred embodiment of my invention and some variants thereof, it will be understood that this is only for the purpose of making the invention more clear and that the invention is not to be regarded as limited to the details of operation described, nor is it dependent upon the soundness or accuracy of the theories which I have advanced as to the reasons for the advantageous results attained. On the other hand, the invention is to be regarded as limited only =0.11 mols. per liter solution per hour.

by the terms of the accompanying claims, in

which it is my intention to claim all novelty inherent therein as broadly as is possible in view of the prior art.

I claim as my invention:

1. The process of making chlorohydrins which comprises establishing and maintaining an at'- mosphere oi an' unsaturated organic compound' in a suitable reaction space\and atomizing-an aqueous solution of tree hypochlorous acid and hydrochloric acid into such chamber so as to react with the unsaturated organic body.

2. 'Ihe process of making chlorohydrins which comprises subjecting an excess of an unsaturated organic compound in a nely divided state to the actionA of an atomized aqueous solution of free hypochlorous acid and hydrochloric acid whereby 'chlorhydrin material is obtained.

' in terms of N. solutions, being less than 0.7.

4. The process of making chlorohydrins which comprises directing a stream of gaseous olefine under pressure against a downwardly flowing finely divided stream of hypochlorous acid and hydrochloric acid dissolved in water, the product of concentration of chlorhydrin and hydrochloric acid, expressed .in terms of. N. solutions, being between about 0.4 and 0.7.

5. 'I'he process of making chlorohydrins which comprises bubbling a current of olene through a liquid body which contains chlorohydrin, di-

recting a finely divided solution of hypochlorous acid and hydrochloric acid dissolved yin water against said liquid body and at all times maintaining an oleflne atmosphere in the reaction zone.

6. The process of making chlorohydrins which comprises contacting a gaseous oleflne with an atomized liquid stream of hypochlorous acid and hydrochloric acid.

I 7. The process of making chlorohydrins which comprises adding suiiicient chlorine to a circulating stream of water so as to maintain a homogeneous liquid system containing at least chlorine, water, hypochlorous acid and hydrochloric acid, introducing said stream in an atomized state into an atmosphere consisting essentially of olefine and maintaining said atmosphere while continuously removing chlorohydrin from the system.

8. The process of making chlorohydrins which comprises reacting a hydrocarbon fraction consisting predominately of butane and butene with hypochlorous acid at a temperature and pressure at which butane is in the liquid state, removing liquid butane charged with chlorohydrin from the sphere of reaction and recovering chlorohydrin from the solvent vehicle.

9. In the process of making chlorohydrins, the step of dehydrating4 the crude chlorohydrin after it has been separated from the aqueous reaction mixture properA which comprises distilling `the aqueous solution in the presence of a paraine hydrocarbon at a temperature below 100 C.

10. In the process of making chlorohydrins, the step of dehydrating the crude aqueous mixture of an individual chlorohydrin after it has been separated from the aqueous reaction mixture proper which comprises distilling the same in the presence of a paraftne hydrocarbon having the same number of carbon atoms to the molecule as the,

predetermined'value lessthan a 1N; solutidn and thereuponvcirculating4 the liquid stream` in a cyclic 'system .while continuously adding water, chlorine and-olene thereto at a rateat which chlorohydrin andformed hydrochloric acid 'are' removed from the system.

12. The process of making chlorohydrins which comprises introduc a nely divided aqueous solution of chlorin into an established and .maintained gaseous body of excess olene, continuing the reaction until the concentration of the resulting -chlorohydrin reaches a predetermined value less than a 1N. solution and thereupon circulating the liquid stream in a cyclic system while continuously adding water. chlorine and oleiine thereto at a rate at which Ychlorohydrin and formed hydrochloric acid are removed from the system.

13. The process of making chlorohydrins which comprises introducing a finely divided aqueous solution of chlorine into an established and maintained gaseous body of excess olene, continuing the'reaction until the concentration of chlorohydrin reaches a predetermined value less than a 1N. solution and thereupon circulating the liquid stream in a cyclic system while continuously adding water, chlorine'and olene thereto at a rate at which chlorohydrin and formed hydrochloric acid are removed from the system, the olene being added in a nely divided state to the dissolved chlorine.

14. The process of making chlorohydrins which comprises introducing a finely divided aqueous stream in a cyclic system while continuously adding water, chlorine and oleine' thereto at a rate at which chlorohydrin andvformed hydrochloric acid are removed from the system, the oleilne being added in the nely divided state to the dissolved chlorine whilethe latter is being atomized into the atmosphere of excess olene.

15. The process of making chlorohydrins which comprises reacting an atomized aqueous solution of hypochlorous acid and hydrochloric acid with an excess of gaseous olefine in the absence of a metal compound. Y

16. The process of making chlorohydrins which comprises reacting a tertiary oleiine in a nely divided state with a finely divided aqueous stream of hypochlorous acid and hydrochloric acid.

17; VThe process of making chlorohydrins which comprises reacting tertiary butylene ini the gas-v eous state with a finely divided aqueous stream of hypochlorous acid and hydrochloric acid.

18. The process of making chlorohydrins which comprises4 establishing and maintaining an atmosphere of substantially isobutylene in a reaction chamber, and introducing therein a nely divided aqueous stream of hypochlorous acid and hydrochloric acid. i I

'1-9. 'I'he process of making chlorohydrins which comprises reacting a: hydrocarbon fraction consisting predominately of olene and parailin hydrocarbons containing the same number of 5carbon atoms to the molecule with hypochlorous acid at a temperature and pressure at which the paraiiin hydrocarbon is in the liquid state, removing the paraiin hydrocarbon containing chlorohydrin from the sphere of reaction and dehydrating and removing chlorohydrin'by distil- 1ing the mixture so as to drive of! the paramn h 21.- The process of making chlorhydrins which drocarbon and the water. comprises subjecting an excess of an unsaturated 20. In a process of making chlorohydrin, the organic compound in a finely divided state to the step of dehydrating a crude, aqueous solution of action of a ilnely divided aqueous solution of 5 chl'orohydrin after it has been separated from the free hypochlorous acid and hydrochloric acid l aqueous reaction mixture proper comprising diswhereby chlorhydrin material is obtained. tilli'ng the same in the presence of a paramn hydrocarbon boiling below 100 C. CARL T. KAU'I'I'ER':

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